STS-99 Day 2 Highlights

Endeavourastronauts began mapping operations on the Shuttle Radar
Topography Mission, which will provide maps of the Earth unprecedented
in accuracy and uniformity. The first swath was begun as the orbiter
crossed over southern Asia and continued until Endeavour flew over the
continent's eastern coast and moved over the northern Pacific
Ocean. The mapping will continue through the mission until the antenna
mast is retracted before landing.

Because of the 24-hour-a-day activity aboard Endeavour, the six
crewmembers are divided into two teams. Blue Team members Dom Gorie,
Janice Voss and Mamoru Mohri began the first mapping swath, covering a
140-mile-wide path, at about 11:31 p.m. Friday. It was the beginning
of coverage of more than 70 percent of the Earth' land surface. The
mapping will cover an area between 60 degrees north and 56 degrees
south, where about 95 percent of the Earth's population lives.

The Red Team, led by Mission Commander Kevin Kregel, includes
Mission Specialists Janet Kavandi and Gerhard Thiele. Their first
shift was intense. It included deployment and checkout of the almost
200-foot mast supporting the outboard antenna structure. It is the
largest rigid structure ever deployed in space. The Red Team began its
sleep period at about 10:45 p.m. Friday and are scheduled to be
awakened at 6:44 this morning.

After mast deployment, tests revealed that the mast's damping
system, designed as a kind of a shock absorber for the mast, was not
working as expected. Flight controllers decided to leave the dampers
in their locked position. Calculations showed that the mast was at no
risk without the dampers activated.

All planned science data takes have been acquired successfully and
all indications from the telemetry show that the radars are performing
nominally. Data has been sent to JPL for analysis and early
indications are that the data is of excellent quality. Additional
reports about mapping results are expected about 12:00 noon CST.

Shortly after 5:30 a.m. Saturday, Voss and Gorie held a news
conference with correspondents from NBC and CNN.

Saturday is scheduled to be the first full day of Shuttle Radar
Topography Mission mapping. Endeavour systems continued to function
normally.

By the time members of Endeavour's Red Team had reached lunchtime on
this first full day in space for the Shuttle Radar Topography Mission,
the radar antennas in the payload bay and at the end of a 200-foot
mast had mapped about 1.7 million square miles (4.5 million square
kilometers) of the Earth's surface, or the equivalent of about half
the area of the United States.

The Red Team - Kevin Kregel, Janet Kavandi and Gerhard Thiele - took
over the mapping operations from their Blue Team counterparts shortly
after waking up about 7 this morning Central Time. Dom Gorie, Janice
Voss and Mamoru Mohri turned in shortly after 2 this afternoon and are
to be awakened at 10:14 tonight. For a few minutes this morning, while
Japanese astronautMohri conducted mapping operations - Gorie and Voss
discussed the mission with CNN and NBC's Today Show.

The crew is working around the clock, in two shifts, to collect data
that will produce maps of the Earth with unprecedented accuracy and
uniformity. Mapping operations will continue for 10 days, and are
proceeding very smoothly. SRTM will cover the area between 60 degrees
north and 56 degrees south, roughly the area between St. Petersburg,
Russia to the north and the tip of South America to the south. The
area to be mapped is home to about 95 percent of the Earth's
population. In all, more than 70 percent of the Earth's surface will
be mapped.

The first X-band image - of the area near White Sands, New Mexico -
was released this afternoon, and scientists expressed their delight
with the quality of the image. X-band images will be posted to the
German Space Agency web site at www.dfd.dlr.de/srtm/html/newtoday_en.htm.

Both the C-band and X-band radars continue to perform as expected.

"The data we've seen so far looks just terrific," said Dr. Michael
Kobrick, project scientist at NASA's Jet Propulsion Laboratory in
Pasadena, CA. "The mapping plan is right on schedule."

Early this afternoon, Kregel fired the shuttle's thruster jets in
a series of pulsed burns to measure the movement of the rigid mast
extending over Endeavour's left wing. Flight controllers reported
the tip of the mast moved only 11 inches, just as predicted, despite
the fact the antenna's dampers remained locked in position. The
firings were necessary to determine how they affect the mast, prior to
upcoming maneuvers to raise Endeavour's orbit.

Endeavour's crew also downlinked launch video from an in-cabin
camera, providing a unique perspective of yesterday's flawless launch.
All of Endeavour's payload and spacecraft systems are continuing to
function normally.